Each time I come to this thread, I hear a song in my head (sorry, I'm a musician). It's this song...You've got to know when to hold 'em, Know when to fold 'em, Know when to walk away, Know when to run. ♫
To me, when I hear the word magnify, I think of an additional piece of glass going between my eye and the subject. That would include microscopes, magnifying glasses, and tele-converters, but not a DX camera sensor.
A DX camera is simply recording an image on an already cropped sensor. To equate that image on an FX sensor, I'd have to manually go in and crop an FX image and resample it; however, while the files may look very much the same to the naked eye, when enlarging both for comparison, that's when the difference may show up.
That's the only thing I was talking about when mentioning the difference in terms of quality. It works the exact opposite in terms of quality the moment the FX can fully frame a shot and you want to take the same shot with the DX.
So whether DX or FX is the better choice depends a lot on the type of photography you do.